.rp-calc-container {
max-width: 800px;
margin: 20px auto;
padding: 30px;
background-color: #ffffff;
border: 1px solid #e0e0e0;
border-radius: 12px;
box-shadow: 0 4px 12px rgba(0,0,0,0.05);
font-family: -apple-system, BlinkMacSystemFont, "Segoe UI", Roboto, Helvetica, Arial, sans-serif;
}
.rp-calc-header {
text-align: center;
margin-bottom: 25px;
color: #2c3e50;
}
.rp-grid {
display: grid;
grid-template-columns: 1fr 1fr;
gap: 20px;
}
@media (max-width: 600px) {
.rp-grid { grid-template-columns: 1fr; }
}
.rp-input-group {
margin-bottom: 15px;
}
.rp-input-group label {
display: block;
margin-bottom: 5px;
font-weight: 600;
font-size: 14px;
color: #555;
}
.rp-input-group input, .rp-input-group select {
width: 100%;
padding: 10px;
border: 1px solid #ddd;
border-radius: 6px;
font-size: 16px;
box-sizing: border-box;
}
.rp-input-group input:focus {
border-color: #3498db;
outline: none;
}
.rp-section-title {
grid-column: 1 / -1;
margin-top: 10px;
margin-bottom: 10px;
font-size: 18px;
font-weight: bold;
color: #34495e;
border-bottom: 2px solid #ecf0f1;
padding-bottom: 5px;
}
.rp-btn {
grid-column: 1 / -1;
background-color: #27ae60;
color: white;
border: none;
padding: 15px;
font-size: 18px;
font-weight: bold;
border-radius: 6px;
cursor: pointer;
transition: background-color 0.2s;
width: 100%;
margin-top: 10px;
}
.rp-btn:hover {
background-color: #219150;
}
.rp-results {
grid-column: 1 / -1;
background-color: #f8f9fa;
border-radius: 8px;
padding: 20px;
margin-top: 25px;
border: 1px solid #e9ecef;
display: none; /* Hidden by default */
}
.rp-result-row {
display: flex;
justify-content: space-between;
padding: 10px 0;
border-bottom: 1px solid #e0e0e0;
font-size: 15px;
}
.rp-result-row:last-child {
border-bottom: none;
}
.rp-highlight {
font-weight: bold;
color: #2c3e50;
}
.rp-main-metric {
text-align: center;
margin-bottom: 20px;
padding-bottom: 20px;
border-bottom: 2px solid #dcdcdc;
}
.rp-main-metric h3 {
margin: 0;
font-size: 16px;
color: #7f8c8d;
text-transform: uppercase;
letter-spacing: 1px;
}
.rp-main-metric .value {
font-size: 36px;
font-weight: 800;
color: #27ae60;
margin-top: 5px;
}
.rp-negative {
color: #c0392b !important;
}
/* Article Styles */
.rp-article-container {
max-width: 800px;
margin: 40px auto;
font-family: -apple-system, BlinkMacSystemFont, "Segoe UI", Roboto, Helvetica, Arial, sans-serif;
line-height: 1.6;
color: #333;
}
.rp-article-container h2 {
color: #2c3e50;
margin-top: 30px;
border-bottom: 2px solid #eee;
padding-bottom: 10px;
}
.rp-article-container h3 {
color: #34495e;
margin-top: 25px;
}
.rp-article-container ul {
background: #f9f9f9;
padding: 20px 40px;
border-radius: 8px;
}
.rp-article-container table {
width: 100%;
border-collapse: collapse;
margin: 20px 0;
}
.rp-article-container th, .rp-article-container td {
border: 1px solid #ddd;
padding: 12px;
text-align: left;
}
.rp-article-container th {
background-color: #f2f2f2;
}
function calculateRentalCashFlow() {
// 1. Get Inputs
var price = parseFloat(document.getElementById('rp_price').value) || 0;
var closingCosts = parseFloat(document.getElementById('rp_closing_costs').value) || 0;
var downPercent = parseFloat(document.getElementById('rp_down_percent').value) || 0;
var interestRate = parseFloat(document.getElementById('rp_interest').value) || 0;
var termYears = parseFloat(document.getElementById('rp_term').value) || 30;
var monthlyRent = parseFloat(document.getElementById('rp_rent').value) || 0;
var annualTax = parseFloat(document.getElementById('rp_property_tax').value) || 0;
var annualInsurance = parseFloat(document.getElementById('rp_insurance').value) || 0;
var monthlyHOA = parseFloat(document.getElementById('rp_hoa').value) || 0;
var vacancyRate = parseFloat(document.getElementById('rp_vacancy').value) || 0;
var maintenanceRate = parseFloat(document.getElementById('rp_maintenance').value) || 0;
var managementRate = parseFloat(document.getElementById('rp_management').value) || 0;
// 2. Calculate Mortgage (Principal & Interest)
var downPayment = price * (downPercent / 100);
var loanAmount = price – downPayment;
var monthlyInterestRate = (interestRate / 100) / 12;
var totalPayments = termYears * 12;
var monthlyPI = 0;
if (interestRate > 0) {
monthlyPI = loanAmount * (monthlyInterestRate * Math.pow(1 + monthlyInterestRate, totalPayments)) / (Math.pow(1 + monthlyInterestRate, totalPayments) – 1);
} else {
monthlyPI = loanAmount / totalPayments;
}
// 3. Calculate Monthly Expenses
var monthlyTax = annualTax / 12;
var monthlyInsurance = annualInsurance / 12;
var monthlyVacancy = monthlyRent * (vacancyRate / 100);
var monthlyMaintenance = monthlyRent * (maintenanceRate / 100);
var monthlyManagement = monthlyRent * (managementRate / 100);
var totalOperatingExpenses = monthlyTax + monthlyInsurance + monthlyHOA + monthlyVacancy + monthlyMaintenance + monthlyManagement;
var totalMonthlyExpenses = totalOperatingExpenses + monthlyPI;
// 4. Calculate Key Metrics
var monthlyCashFlow = monthlyRent – totalMonthlyExpenses;
var annualCashFlow = monthlyCashFlow * 12;
// NOI = Annual Income – Operating Expenses (Excluding Mortgage)
var annualNOI = (monthlyRent * 12) – (totalOperatingExpenses * 12);
// Cap Rate = NOI / Purchase Price
var capRate = (price > 0) ? (annualNOI / price) * 100 : 0;
// Cash on Cash Return = Annual Cash Flow / Total Cash Invested
var totalCashInvested = downPayment + closingCosts;
var cocReturn = (totalCashInvested > 0) ? (annualCashFlow / totalCashInvested) * 100 : 0;
// 5. Update UI
var cashFlowEl = document.getElementById('rp_monthly_cashflow');
cashFlowEl.innerText = formatCurrency(monthlyCashFlow);
if(monthlyCashFlow < 0) {
cashFlowEl.classList.add('rp-negative');
} else {
cashFlowEl.classList.remove('rp-negative');
}
document.getElementById('rp_noi').innerText = formatCurrency(annualNOI);
document.getElementById('rp_cap_rate').innerText = capRate.toFixed(2) + "%";
var cocEl = document.getElementById('rp_coc');
cocEl.innerText = cocReturn.toFixed(2) + "%";
if(cocReturn < 0) cocEl.classList.add('rp-negative');
else cocEl.classList.remove('rp-negative');
document.getElementById('rp_display_income').innerText = formatCurrency(monthlyRent);
document.getElementById('rp_display_mortgage').innerText = formatCurrency(monthlyPI);
document.getElementById('rp_display_opex').innerText = formatCurrency(totalOperatingExpenses);
// Show results
document.getElementById('rp_result_box').style.display = 'block';
}
function formatCurrency(num) {
return new Intl.NumberFormat('en-US', { style: 'currency', currency: 'USD' }).format(num);
}
Mastering the Numbers: A Guide to Rental Property Cash Flow
Real estate investing is often touted as a path to financial freedom, but buying a property doesn't automatically guarantee profit. The difference between a savvy investment and a money pit lies in the math. This Rental Property Cash Flow Calculator is designed to help investors strip away the emotion and look strictly at the numbers to determine if a specific property is viable.
How to Interpret Your Results
Once you input your property details, our calculator provides four critical metrics. Understanding what these mean is essential for making informed decisions.
1. Monthly Cash Flow
This is your "take-home" pay from the property. It represents the money left over after all bills—mortgage, taxes, insurance, and maintenance reserves—are paid. A positive cash flow means the property pays for itself and generates income. A negative cash flow means you are paying out of pocket every month to hold the asset.
2. Net Operating Income (NOI)
NOI is a measure of the property's profitability before financing costs are considered. It is calculated by subtracting all operating expenses from the gross income. Lenders often look at NOI to determine if a property generates enough income to cover the debt service.
3. Cap Rate (Capitalization Rate)
The Cap Rate measures the natural rate of return on the property assuming you paid for it in all cash. It helps you compare the profitability of different properties regardless of how they are financed. A higher Cap Rate generally indicates a higher potential return (often accompanied by higher risk).
- Formula: NOI / Purchase Price
- Target: Many investors look for Cap Rates between 4% and 10%, depending on the market location and asset class.
4. Cash on Cash Return (CoC)
This is arguably the most important metric for investors using leverage (loans). It measures the return on the actual cash you invested (down payment + closing costs). It answers the question: "If I put $50,000 into this deal, what percentage of that do I get back this year?"
- Formula: Annual Pre-Tax Cash Flow / Total Cash Invested
- Target: A common goal is 8-12%, though this varies by strategy.
The "Hidden" Expenses New Investors Forget
A common mistake when manually calculating cash flow is omitting variable expenses. Our calculator includes fields for these crucial categories:
| Expense |
Why Include It? |
Typical Range |
| Vacancy |
Properties don't stay rented 365 days a year. You need to budget for turnover periods. |
5% – 10% |
| Maintenance/CapEx |
Budgeting for repairs (leaky faucets) and capital expenditures (new roof, HVAC) is mandatory. |
5% – 15% |
| Management Fees |
Even if you self-manage, you should budget for this. Your time has value, or you may hire a PM later. |
8% – 12% |
Example Scenario: Is This a Good Deal?
Let's look at a realistic example to see how the numbers play out.
Imagine you buy a single-family home for $300,000. You put 20% down ($60,000) and pay $6,000 in closing costs. Your interest rate is 6.5%. The house rents for $2,500/month.
After paying the mortgage (~$1,516), taxes ($250), insurance ($100), and setting aside 20% of rent for vacancy/repairs/management ($500), your total expenses might be around $2,366.
Result: Your monthly cash flow is roughly $134. Your Cash on Cash return is approximately 2.4%.
Is this good? For a pure cash-flow investor, likely not—the return is lower than a high-yield savings account. However, an appreciation-focused investor might accept this lower cash flow if the property is in a high-growth area. Using a calculator allows you to adjust your offer price until the returns meet your specific investment goals.
Frequently Asked Questions
What is the 1% Rule?
The 1% rule is a quick screening tool used by investors. It suggests that the monthly rent should be at least 1% of the purchase price. For a $200,000 home, the rent should be $2,000. While harder to find in today's market, properties meeting this rule usually cash flow well.
Should I include appreciation in my calculation?
This calculator focuses on cash flow. Appreciation is speculative; while it builds wealth over the long term, you cannot pay monthly bills with appreciation. It is safer to buy for cash flow and treat appreciation as the "icing on the cake."